The present invention relates to electrical connections internal to hermetic compressor assemblies and methods of quickly and effectively installing same, particularly with regard to connectors designed to protect against electrical arcing across carbon deposits which may be formed within the compressor assembly.
The terminal assembly extending through the sealed shell or housing of a hermetic compressor includes a plurality of conductor pins which extend through apertures located in the terminal body. The terminal body is usually welded or brazed into an aperture provided in the compressor assembly housing. The conductor pins are secured within these apertures, and are electrically insulated from the terminal body and the housing, by fused glass insulators. An electric motor having a stator and a rotor is located within the housing, the rotor operatively coupled to a compression mechanism. The interior ends of the conductor pins are connected to lead wires which are connected to the windings of the motor stator. The exterior ends of the conductor pins are selectively connected, as through a switch device, to a source of electrical power. Thus, the motor is energized by the external power source through the terminal body, the lead wires, and the electrical connections therebetween. The electrical connections typically include an electrical connector attached to each lead wire which is engaged with a corresponding conductor pin. A plurality of connectors, and portions of their respective lead wires, are normally assembled into, and housed by, a cluster block which comprises the connector assembly. The cluster block is dielectric, usually constructed from an injection molded plastic, and facilitates quick assembly of the lead wires to the terminal assembly. The cluster block insulates the electrical connectors therein from each other, from the terminal assembly, and from the compressor housing, to a substantial degree. Usually, the interior of the cluster block is formed with separated passageways, each of which receives one lead wire, and recesses for each of the connectors attached to the ends of the lead wires. Passageways leading to these connectors are provided through the cluster block material, the conductor pins of the terminal assembly extending therethrough.
During compressor operation, carbon or other conductive deposits from the motor may collect on the interior surfaces of the housing and terminal assembly. These deposits may provide a conductive path between elements at differing electrical potentials, and a short circuit or arc may develop along that path. Such arcing results in resistive heating of the deposits along the conductive path, which heats the elements on which the deposits collect. Such heating is known to sometimes cause the fused glass insulators about the conductor pins to melt, thereby causing the compressor housing to leak pressurized gas at the terminal assembly.
Prior hermetic compressor assemblies often include some means for impeding such arcing, these means are usually designed to prevent the conductive deposits from collecting on the interior surface of the terminal assembly and its glass insulators. These means include electrical connector or cluster block assemblies, through which the lead wires are attached to the interior ends of the conductor pins, which, when assembled to the terminal assembly, substantially covers same. Prior connector assemblies have not completely precluded the formation of a conductive path between the lead wire ends or electrical connectors within the cluster block, and the terminal body or compressor housing.
Some of these connector assemblies means may include sealing features which help prevent the conductive deposits from entering the interior of the terminal assembly past its interface with the cluster block. One such cluster block assembly includes a cylindrical exterior wall portion which sealingly engages the cylindrical interior surface of the terminal body, as by an interference fit; the cylindrical interface may also include additional sealing means such as an O-ring. A problem associated with prior connector assemblies which sealably engage the terminal assembly in this manner is that they may be improperly installed, the proper seating of the block relative to the terminal assembly being hindered by the interference fit between the terminal body and the cluster block, or the O-ring therebetween.
One method of connecting prior connector assemblies involves an assembly operator manually forcing the cluster block into its fully installed position within the terminal body. Other methods involve the use of tools such as pliers or a hammer to make this connection. There are problems associated with these prior installation techniques: When manually installing the cluster block, the person installing the block may not be physically able to force the cluster block into the terminal body far enough to create the sealing engagement required to prevent debris from entering the terminal assembly. When using pliers or a hammer to effect installation of the connector assembly, damage to the cluster block, such as deformation, cracking or splitting thereof, may occur. Thus, improper installation of the connector assembly to the terminal assembly may result in an open circuit, carbon being deposited on the interior of the terminal assembly, or damage to the assembled parts.
It is desired to provide a connector assembly and an installation method therefor, which ensure that the connector assembly is properly installed to the terminal assembly easily and consistently, protect against the formation of undesirable conductive paths, and thus electrical arcing, within the compressor assembly, and avoid the above-mentioned shortcomings of previous connector assemblies and installation methods.
The present invention relates to a connector assembly which is installed into the terminal assembly and protects against the formation of undesirable conductive paths thereacross, which may result in electrical arcing. The present invention also relates to a method for installing the connector assembly easily and consistently, and without damage to the connector assembly. The cluster block of the inventive connector assembly is provided with a feature engaged by an tool during installation; through use of the inventive method, the connector assembly is properly installed easily and consistently, and without the risk of damage thereto.
The tool includes a body portion having two legs, one of which is outside the compressor housing during assembly and supports a pneumatic cylinder, the other of which is inside the compressor housing during assembly and engages the cluster block. The latter leg is provided with a recess or a protrusion which respectively engages a protrusion or a recess provided on the cluster block. The connector assembly is loosely assembled onto the conductor pins of the terminal assembly. As the pneumatic cylinder advances toward the outer surface of the compressor housing, the cluster block is forced into sealing engagement with the terminal body. The force exerted on the cluster block by the tool is automatically controlled to ensure proper seating of the cluster block relative to the terminal body, thereby ensuring that the interior of the terminal assembly is protected from carbon deposits forming therein, and to prevent damage to the assembled parts.
The present invention provides a method of installing a connector assembly relative to a terminal assembly of a hermetic compressor assembly including: aligning the connector assembly with the terminal assembly; positioning an installation tool on the connector assembly; actuating the installation tool; and seating the connector assembly into the terminal assembly.
The present invention further provides a method of installing a connector assembly relative to a terminal assembly of a hermetic compressor assembly including: aligning the connector assembly with the terminal assembly; positioning an installation tool on the connector assembly; pneumatically applying force to the connector assembly through the installation tool until a predetermined pneumatic pressure has been reached; seating the connector assembly into the terminal assembly when or before the predetermined pressure has been reached; and retracting the tool after the connector assembly has been seated into the terminal assembly.
The present invention also provides a tool for installing a connector assembly to the terminal assembly of a hermetic compressor assembly. The tool includes a body member which supports a pneumatic cylinder. Means are provided on the body member for ensuring proper alignment of the tool with the connector assembly during installation of the connector assembly to the terminal assembly.